Cassette



Dec. 31, 1935. F; T. POWERS CASSETTE Filed Oct. 29, 1931 INVENTOR vspring clips from the back Patented Dec. 31, 1935 UNITED As'r-.frss

iPAT/ENT QFF'QE 5 Claims.

My invention relates tothe radiographic art and more particularly to amethod and an apparatus whereby greatly. increased speed in makingradiographs may be attained, especially of a larger'number of successivepatients.

Objects and advantages of the invention will be set forth inY parthereinafter and in part will be obvious hereirom, or. may be learned bypractice with the invention, the same beingrealized and attained bymeans .ofthe instrumentalities and combinations pointed out in theappended claims.

The methods and apparatus heretofore in use for making radiographs,while well adapted to the production of excellent results, are notadapted .to the rapid making of many consecutive radiographs ofsuccessive patients with their widely varying anatonroal characteristicsin a minimum oftime. The present method is slow and cumbersome. Thisslowness may be attributed largely to the holders,` called cassettes,used for holding the ray sensitive medium in position during exposuretothe rays, and to the form in which the sensitive medium is used. Thepresent customary method is to place a sheet of sensitive membrane, suchas a` sensitized lm, of the size of the radiograph to be made, in alight tight cassette or holder, in intimate contactwith one or twointensifying `screens of fluorescent material, where it is held in placeby pressure appliedby of the cassette. This operation must.' beperformed in a dark room, as the sensitive medium is sensitive to lightrays as well as to X-rays. When. about to make a radiograph the loadedcassette is placed in such positionthat the object to be radiographed isin proper relation to ,the .cassette and the source of X- rays.Theexposure is then made andthe cassette returned tothe darkroom forunloading and' reloading. .The exposed Asheet of sensitive membrane isplacedin a specially. constructed frame or holder in which thesensitized'membrane is clamped at each one of its .four corners byspring clamps, which hold the membrane in a substantially flat,distended position for development, fixing, washing and drying. Theentire series of operations described above may, With the best of theapparatus and equipment now on the market, be completed in abouthalf anhour, or if sufficient assistance is provided so that .the operationsaredivided up between various operators, .the time per patient or perradiograph may be appreciably reduced. In some well equipped andeciently operatedlaboratories radiographs of anatomical objects, suchfor example, as the lung entity in the upper half of the humantorso,

. to-sizel lm, loading .f madeto hold but 011e sheet of film atveloping, fixing, Washing and drying each radioeach radiograph,

,a suitable spool,

or centres Within my new cassette.

; from` one position within the cassette a have beenlmade at an averagerate .of from three to five per hourthroughoutthe day. Smaller objects,such .as hands .or extremities, may be madeat a faster rate.

The present. method is a one-at-a-time method Y A since each operationor step of the method is per- `.formed `on;but one .radiograph at a:cassette holdsbut onesheet of sensitive medium; :it must be loaded andunloaded one-at-a-time for each radiograph; the sensitive sheetsdeveloped one at a time, washed, fixed and .one atatime, examined andfiled one at a l But with'mynew method and cassette I am able time. The

are dried time.

to :take anatomically identical or corresponding radiographsi` such as.the human lung cavity, at .the rate of fromtwo to three oneu hundredand. twenty to one seighty per hour, notwithstanding the wide differ-V.; ences..in. their. anatomical characteristics. ...great increase .inrate of production is one of the primary,` objects of my invention. Itis accom- .:panied Abya corresponding reduction in the cost per minute,or from hundred and This of labour. forsma graphs.

vThe invention lies in ratus for carrying out the slow, cumbersome g andfinishing the radioa process and in appathe process. Instead of processof handling cutand unloading cassettes a time, de-

graph separately, in a continuous I use my sensitized membrane strip ofthe Width desired for but long enough to make a plu- YThis sensitizedstrip is placed on which is mounted on a mandrel By suitable mechanismin fthe cassette this roll of sensitized lmis. moved proper distances ateach movement to another wound up passed step by step rality of them.

position where the exposed portion Lis on another roll, having `throughthe. exposure-position and received a number. of. exposuresLto rays.posedllm is then removedfrom the cassette in The roll of exdaylight anddeveloped in a well known type of developing machine,'1xed, washed anddried, and may be examined while'still in tinuous strip,

the form of a conthe whole process being performed at sucha rate thatmany hundreds of finished,

. ready to examine radiographs may be turned out each working. day. v

My new process makes it possible to take radiographs of large groups ofindividuals, such as the pupils of a school or the employees of afactory, or an army of soldiers at the rate of from one hundred andtwenty to one hundred and eighty per hour,-a rate never approached byany known method. The importance of this new method in the war againsttuberculosis which admittedly can best be diagnosed by X-ray methods isobvious.

The full beneiits of my new method are best attained when it is employedin conjunction with my X-ray apparatus described in my co-pendingapplication Serial No. 589,401.

I will now describe in detail my new process and cassette, so that oneskilled in the art may make and use the same.

In the drawing like symbols indicate the same or similar parts, andarrows indicate direction of movement or rotation.

Fig. l is a side View of the cassette. Fig. 2 is a sectional view on theline AA of Fig. 3 showing internal parts. Fig. 3 is a front View withportions broken away to expose internal parts. Fig. 4 is a sectionaldetail of the front portion of the cassette on the line BB of Fig. 3.

In Fig. 2 is shown the roll of sensitized medium, such as X-ray lm on aspool I mounted on a removable shaft 2, which is supported in bearings2A attached to the inside of the main case 3, consisting of a box-likestructure of any suitable material, such as wood or metal, and lined orcovered completely with sheet lead, of a thickness sufficient to safelyprotect the sensitive membrane from both direct and reflected rays. Forlightness and strength I prefer to construct the case 3 of sheetaluminum, and I protect the interior from rays by lining the frontportion with sheet lead 1/3" hick, the sides, top and bottom 5, withsheet lead 53e" thick, and the back 6, with sheet lead g" thick.Obviously the amount of protection needed will vary with the type ofservice for which the cassette is to be used; but I nd the abovespecified protection suicient for anatomical radiographs, using not overmlliamperes and 85 kilovolts peak. On the front of the case is arectangular opening and having no lead protection. The size of thisopening is the size of the largest radiograph to be taken by theapparatus. The opening is covered by a removable plate 1 of suitablematerial, practically transparent to X-rays, such for example, asaluminum or a thermo-plastic composition. This plate is held in place bythe l Vstuds and thumb nuts 8. To the inner surface of the removablefront plate 1 is securely attached an intensifying screen 9 of wellknown type. On shafts IU and l l are fixed bell cranks I2, one arm ofeach of which is attached to one of four brackets I3, attached to thepressure member le, of metal or the like, shaped like a shallow pan withsides l5 within which is a lling IB, of a resilient yielding material,such, for example, as felt or soft sponge rubber. To the surface of thislling I may also attach an intensifying screen 9A when I desire to use asensitive membrane which is sensitized on two sides. Or I may omiteither the screen 9 or screen 9A when I desire to l use a sensitivemembrane which is sensitized on one side only. The upper and lower bellcranks l2 are connected on each side of the case by vertical rods I7,and the upper shaft Il, which extends through the case 3, is providedwith a hand lever I8, on the outside of thecase, by the movement ofwhich the pressure member Iii, with its resilient filling material maybe moved to ward or away from the front plate 1, to either position Bindicated by the dotted lines in Fig. 4,

Vor to position A, in which position it is pressed tightly against thefront plate in position A indicated by full lines in Fig. 4.

Below the pressure member Ill is a roller i9 mounted on a shaft 20, oneend of which extends through the side of case 3 and carries a pointer 52l, whichcooperates with a dial 22, to indicate the length of sensitizedfilm moved foward as hereinafter described.

A wind up spool 23, is mounted on a shaft 24, one end of which extendsthrough the side of case 10 3 and is provided with a crank handle 25, bymeans of which the sensitive membrane maybe wound Vup on the spool 23.Above the pressure member lli, is a guide bar 25, extending across thecase from side to side, with its front edge a short dis- 15 tance, forexample 1/2 inch, from the inside of the front of the case. On shafts 2and 24 are xed two grooved pulleys 2 and 28, connected with a cross belt29. On shaft 24 is also fixed a toothed ratchet wheel 3G, engaging apawl 3l, attached to 20 the case. .On the top'of the case is provided awindow consisting of a movable cover 32 of lead and an inserted sheet ofruby glass 33. The back of the case consists of two doors 37, lined withlead, carried by the hinges 34. The hand lever i8 25 is provided withcooperating catches 35 and 33 attached to the side of the case by meansof which the hand lever may be releasably held in position at eitherside of its arc of, movement. Having described in detail theconstruction of one form 30 of my new cassette, I will now describe itsmethod of operation.

A roll of sensitive membrane wound upon'the spool l is placed upon theremovable shaft 2 and the shaft and spool are dropped into place in the35 bearing 2A. The roll of membrane is provided with a strip of opaquepaper or other suitable opaque membrane on the outside of the roll. Thisopaque membrane, called a leader is several feet long and permitsloading the cassette in 40 daylight in a manner well known and commonlyused in loading hand cameras. The leader is passed over the guide 26 anddown throughV the space between the pressure member M, and the plate l,over the measuring roll i9 and to the 45 wind-up spool 23, to which itis attached by means of a strip of adhesive tape or other convenientmethod. While thisv loading operation is in progress the pressuremember, by movement of the lever I8, to engage the catch 36, is placedin its 50 position away from the plate 1, or the plate 'i may be removedfrom the front of the cassette to facilitate the operation. The doors3l, are then closed and by means of the crank 25, the spool 23, isrotated in a clockwise direction to wind up 55 the leader and pull overthe sensitive membrane to whichrit is attached. The cover 32, of thewindow is lifted, giving a view through the ruby glass 33 permitting theoperator to observe when the leader has passed and the sensitivemembrane 6( comes into View. Additional turns of the crank 25, are madeuntil the movement of the pointer 2l, indicates that the end of thesensitive membrane has passed the exposure position in front of thepressure member lli. The lever i8, is then '6i moved to engage the catch35, and cause the pressure member with its resilient filling i6, topress the sensitive membrane into intimate contact with the intensifyingscreen or screens 9. The apparatus is now ready for the making of aradio- 7 graph upon that portion of the sensitive membrane beingcompletely shielded and protected from action of the rays bythe leadcoverings de- 7 CII scribed above. After exposure to the rays, the leverI8, is released from the catch 35, and moved over to engage the catch36, thus moving the face of the lling of the pressure chamber I4, toposition B shown by the dotted lines in Fig. 4, and releasing thepressure on the sensitive membrane and leaving the membrane in a slackor loose condition between the guide bar 26, and the measuring roll I9,in the position indicated by the dotted lines C in Fig. 4. This featureof the design and operation of the cassette is of great importance asthe loose or slack strip of membrane l has an opportunity to alignitself and relieve any tendency to creep to one side or other of themeasuring roll. It has been found that when the strip of sensitivemembrane is wound up under tension with no slack interval for selfadjustment, it has a tendency to creep to one side or the other of thewind-up spool 23, and burr the edge of the membrane. The crank 25, isagain turned in a clockwise direction and at the instant of starting thebelt 29 acts to turn the spool I in the opposite direction, taking allslack out of the membrane between the two spools and drawing it tautover the guide bar 26, and the measuring roller I9. The friction of thebelt 29, on the pulleys 2'I and 23 is not suiicient to prevent movingthe membrane, but only suflicient to keep it taut. The crank 25, isturned until the pointer 2I indicates by its movement over the dial 22,that the entire exposed portion of the membrane has been moved out ofits exposure position into a shielded position and an unexposed portionmoved into exposure position. The ratchet 30, and pawl 3I, prevents thespool 23 from reversing its direction of rotation and permitting themembrane to become slack upon releasing the crank 25. The lever I8 isthen moved over to engage the catch 35, thus pressing the membrane againinto intimate contact with the intensifying screen and the apparatus isagain ready for the making of a radiograph. These operations arerepeated successively until all of the sensitive membrane on the spool Ihas passed the exposure position. To the end of the membrane is attacheda second leader of opaque paper, which is now wound up on the outside ofthe membrane on spool 23, by means or" the crank 25, and the spool ofexposed membrane is ready for removal from the cassette and for finaldevelopment.

It will be obvious to one skilled in the art that many modiications inthe construction and arrangement of parts which I have shown in therawing may be made to adapt my cassette to a variety of uses withoutdeparting from the spirit of the invention, as set forth in thefollowing claims.

I claim:

1. A cassette for X-ray radiography with provision for handling andexposing successive lengths of a long strip of sensitized material, thecassette comprising' a casing having an X-ray permeable window therein,winding reels within the casing and operating means including a handleexternal of the casing for winding measured lengths of said strip pastsaid window onto one of said reels and from oi the other reel, meansother than said strip tending to rotate said latter reel in a directionto create t-ension in the strip along its length and in the sectionthereof extending between the two reels during the winding operation andmeans within the casmg movable into and out of a predetermined positionto press an entire area of the strip corresponding to the exposure areainto a plane for exposure to X-rays through said window in the casing.

2. A cassette for X-ray radiography with provision for handling andexposing successive lengths of a long strip of sensitized material, thecassette comprising a casing having an X-ray permeable window therein,winding reels within the casing and operating means including a handleexternal of the casing for winding measured lengths of said strip pastsaid window onto one of said reels and from off the other reel, meansother than said strip controlled by said operating means tending torotate said latter reel in a direction to create tension in the stripalong its length and in the section thereof extending between the tworeels during the winding operation and means within the casing movableinto and out of a predetermined position to press an entire area of thestrip corresponding to the exposure area into a plane for exposure to X-rays through said window in the casing.

3. A cassette for X-ray radiography with provision for handling andexposing successive lengths of a long strip of sensitized material, thecassette comprising a casing having an X-ray permeable window therein,winding reels within the casing and operating means including a handleexternal of the casing for windingmeasured lengths of said strip pastsaid window onto one of said reels and from 01T the other reel, africtional driving connection between said winding reels for creatingtension in the strip along its length and in the section thereofextending between the two reels during the winding operation and meanswithin the casing movable into and out of a predetermined position topress an entire area of the strip corresponding to the exposure areainto a plane for exposure to X- rays through said window in the casing.

4. A cassette for X-ray radiography with prof vision for handling andexposing successive lengths of a long strip of sensitized material, thecassette comprising a casing having an X-ray permeable window therein,winding reels within the casing and operating means measured lengths ofsaid strip past said window onto one of said reels and from off theother reel, means within the casing movable into and out of apredetermined position to press an area of the strip into a plane forexposure to X-rays through said window in the casing, said lastmentionedmeans when out of said predetermined position producing slack in saidstrip, and strip tensioning means extending between said reels tendingto rotate said latter reel to take up a part of said slack, said meansbeing operative upon winding of the strip onto said rst-mentioned reel.

5. A cassette for X-ray radiography with provision for handling andexposing successive lengths of a long strip of sensitized material, thecassette comprising a casing having an X-ray permeable window therein,winding reels within the casing, means for winding said strip oir onereel and onto the other, a pressure member adapted to engage an area ofsaid strip registering with said window and to be withdrawn from suchengagement and thereby effect a slackening of the tension in said stripbetween said reels, and means in association with said latter reeltending to rewind a part of the slack portion of said strip on saidlatter reel to thereby maintain proper alignment of the strip with thereels.

FRANK 'I'. POWERS.

for winding

